use diesel::prelude::*;
use crate::{DbConnection, QueryResult};
use crate::schema::players;

/// Representation of a player in database
#[derive(Debug, Queryable, Serialize)]
pub struct Player {
    /// DB Identitier
    pub id: i32,
    /// Full name of the character
    pub name: String,
    /// Amount of gold coins owed to the group.
    /// Taking a looted items will increase the debt by it's sell value
    pub debt: i32,
    /// Count of copper pieces
    pub cp: i32,
    /// Count of silver pieces
    pub sp: i32,
    /// Count of gold pieces
    pub gp: i32,
    /// Count of platinum pieces
    pub pp: i32,
}

pub struct Players<'q>(pub &'q DbConnection);

impl<'q> Players<'q> {

    pub fn all(&self) -> QueryResult<Vec<Player>> {
        players::table
            .load(self.0)
    }

    pub fn add(&self, name: &str, wealth: f32) -> QueryResult<Player> {
        diesel::insert_into(players::table)
            .values(&NewPlayer::create(name, wealth))
            .execute(self.0)?;
        players::table
            .order(players::dsl::id.desc())
            .first(self.0)
    }
}

pub struct AsPlayer<'q>(pub &'q DbConnection, pub i32);

impl<'q> AsPlayer<'q> {
    pub fn update_wealth(&self, value_in_gp: f32) -> QueryResult<Wealth> {
        use crate::schema::players::dsl::*;
        let current_wealth = players
            .find(self.1)
            .select((cp, sp, gp, pp))
            .first::<Wealth>(self.0)?;
        let updated_wealth = Wealth::from_gp(current_wealth.to_gp() + value_in_gp);
        // Difference in coins that is sent back
        let difference = Wealth {
            cp: updated_wealth.cp - current_wealth.cp,
            sp: updated_wealth.sp - current_wealth.sp,
            gp: updated_wealth.gp - current_wealth.gp,
            pp: updated_wealth.pp - current_wealth.pp,
        };
        diesel::update(players)
            .filter(id.eq(self.1))
            .set(&updated_wealth)
            .execute(self.0)?;
        Ok(difference)
    }

    pub fn update_debt(&self, value_in_gp: i32) -> QueryResult<()> {
        diesel::update(players::table.find(self.1))
            .set(players::dsl::debt.eq(
                players::dsl::debt + value_in_gp
            ))
            .execute(self.0)?;
        Ok(())
    }
}


/// Unpack a floating value of gold pieces to integer
/// values of copper, silver, gold and platinum pieces
///
/// # Note
///
/// The conversion is slightly different than standard rules :
/// ``` 1pp = 100gp = 1000sp = 10000 cp ```
///
fn unpack_gold_value(gold: f32) -> (i32, i32, i32, i32) {
    let rest = (gold.fract() * 100.0).round() as i32;
    let gold = gold.trunc() as i32;
    let pp = gold / 100;
    let gp = gold % 100;
    let sp = rest / 10;
    let cp = rest % 10;
    (cp, sp, gp, pp)
}

/// State of a player's wealth
///
/// Values are held as individual pieces counts.
/// Allows conversion from and to a floating amount of gold pieces.
#[derive(Queryable, AsChangeset, Debug)]
#[table_name = "players"]
pub struct Wealth {
    pub cp: i32,
    pub sp: i32,
    pub gp: i32,
    pub pp: i32,
}

impl Wealth {
    /// Unpack individual pieces counts from gold value
    ///
    /// # Examples
    /// ```
    /// # use lootalot_db::models::Wealth;
    /// let wealth = Wealth::from_gp(403.21);
    /// assert_eq!(wealth.as_tuple(), (1, 2, 3, 4));
    /// ```
    pub fn from_gp(gp: f32) -> Self {
        let (cp, sp, gp, pp) = unpack_gold_value(gp);
        Self { cp, sp, gp, pp }
    }
    /// Convert total value to a floating value in gold pieces
    ///
    /// # Examples
    /// ```
    /// # use lootalot_db::models::Wealth;
    /// let wealth = Wealth{ pp: 4, gp: 3, sp: 2, cp: 1};
    /// assert_eq!(wealth.to_gp(), 403.21);
    /// ```
    pub fn to_gp(&self) -> f32 {
        let i = self.pp * 100 + self.gp;
        let f = (self.sp * 10 + self.cp) as f32 / 100.0;
        i as f32 + f
    }
    /// Pack the counts inside a tuple, from lower to higher coin value.
    pub fn as_tuple(&self) -> (i32, i32, i32, i32) {
        (self.cp, self.sp, self.gp, self.pp)
    }
}

/// Representation of a new player record
#[derive(Insertable)]
#[table_name = "players"]
pub(crate) struct NewPlayer<'a> {
    name: &'a str,
    cp: i32,
    sp: i32,
    gp: i32,
    pp: i32,
}

impl<'a> NewPlayer<'a> {
    pub(crate) fn create(name: &'a str, wealth_in_gp: f32) -> Self {
        let (cp, sp, gp, pp) = Wealth::from_gp(wealth_in_gp).as_tuple();
        Self {
            name,
            cp,
            sp,
            gp,
            pp,
        }
    }
}

#[cfg(test)]
mod tests {

    #[test]
    fn test_unpack_gold_values() {
        use super::unpack_gold_value;
        let test_values = [
            (1.0, (0, 0, 1, 0)),
            (1.23, (3, 2, 1, 0)),
            (1.03, (3, 0, 1, 0)),
            (100.23, (3, 2, 0, 1)),
            (-100.23, (-3, -2, -0, -1)),
            (10189.23, (3, 2, 89, 101)),
            (-8090.20, (0, -2, -90, -80)),
        ];

        for (tested, expected) in test_values.into_iter() {
            assert_eq!(unpack_gold_value(*tested), *expected);
        }
    }

}